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Combustion Synthesis and Densification of NiAl/TiB_2 Composites

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Journal of Wuhan University of Technology(Materials Science) 2002年第1期17卷 4-9页

作者：王为民 wuhanuniversityoftechnology

A suitable combustion synthesis and densification process was designed to fabricate dense NiAl/ TiB2 composites from Ni-Al- Ti-B system. Combustion synthesis processing and microstructure characteristics of products were studied in detail. The results show that the amount of TiB2 ceramics has a great influence on the combustion synthesis processing and microstructure; with the increase of the amount of TiB2 ceramics, the combustion temperature and combustion velocity increase rapidly. The volume of synthesized products and the grain size of ceramics particle size are also affected by the amount of TiB2 ceramics. TiB2 ceramics fiber can be produced in this synthesis system. The dense NiAl/ TiB2 composites with residual porosity of no more than 1% are fabricated by the combustion synthesis and hot pressing, the mechanical properties of the dense NiAl/ TiB2 composites increase with increase of the amount of TiB2 ceramics.

关键词： NiAl/ TiB2 composites combustion synthesis and hat pressing microstructure and mechanical properties

Preparation of Ti_3SiC_2 with Aluminum by Means of Spark Plasma Sintering

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Journal of Wuhan University of Technology(Materials Science) 2003年第1期18卷 37-40页

作者：朱教群 wuhanuniversityoftechnology

Polycrystalline bulk Ti 3SiC 2 material with a high purity and density was fabricated by spark plasma sintering from the elemental powder mixture with starting composition of Ti 3Si 1-x Al xC 2,where x=0.05-0.2.X ray diffraction patterns and scanning electron microscopy photographs of the fully dense samples show that a proper addition of aluminum promotes the formation,and accelerates the crystal growth rate of Ti 3SiC 2,consequently results in a high purity of the prepared *** synthesized Ti 3SiC 2 is in plane shape with a size of about 10-25μm in the elongated *** solution of aluminum decreases the thermal stability of Ti 3SiC 2,and lowers the temperature of Ti 3SiC 2 decomposeing to be 1300 ℃.

关键词： titanium silicon carbide spark plasma sintering preparation

Random Time Dependent Resistance Analysis on Reinforced Concrete Structures

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Journal of Wuhan University of Technology(Materials Science) 2002年第4期17卷 58-60页

作者：管昌生 wuhanuniversityoftechnology

The analysis method on random time dependence of reinforced concrete material is introduced,the effect mechanism on reinforced concrete are discussed,and the random time dependence resistance of reinforced concrete is ***,the corrosion of steel bar in reinforced concrete structures is analyzed.A practical statistical method of evaluating the random time dependent resistance,which includes material,structural size and calculation influence,is also *** addition,an example of predicting random time dependent resistance of reinforced concrete structural element is given.

关键词： random analysis time dependent resistance reinforced concrete

Preparation of the Heat Resistant Adhesive of NBR Modified BMI

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Journal of Wuhan University of Technology(Materials Science) 2002年第1期17卷 69-71页

作者：黄志雄 wuhanuniversityoftechnology

A Kind of homogeneous resin , which can be used as thermal resistant adhesive and matrix for composite, was prepared by bis (4-maleimidophenyl) methane ( BMI), 4,4’ -diaminodiphenylmethane( DDM), aniline (An), phenol type epoxy resin ( F-51 ) and nitrile -butadiene rubber ( NRR) through solution copolymer-ization . The reaction from prepolymerization to curing of the resin system was studied. And the factors such as raw material ratio and curing temperature, which affect thermal resistance and adhesives of cured product, were also analyzed. SEM and IR spectra were utilized to discuss the mechanisms of toughness and reaction of modified BMI.

关键词： adhesive phenylamine phenoltype epoxy resin nitrile-butaiene rubber

Degration of Partially Stabilized Zirconia Ceramics underan Applied Stress

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Journal of Wuhan University of Technology(Materials Science) 2003年第1期18卷 17-19页

作者：沈强 wuhanuniversityoftechnology

Partially stabilized zirconia ceramics were sintered using fine powder of ZrO 2 3mol%Y 2O 3 prepared by the chemical co precipitation *** tetragonal to monoclinic phase transformation in ZrO 2 ceramics during the aging in boiling water and the effect of an applied stress of 100MPa were mainly *** degradation of ZrO 2 ceramics is considered to be caused by the reaction between Y 2O 3 and H 2O,which leads to a decreasing in the stability of tetragonal phase of ZrO *** is found that the tensile stress improves the driving force of the phase transformation and accelerates the degradation while the compressive stress has no obvious effect on the degradation.

关键词： degradation partially stabilized zirconia applied stress

Random Boundary Simulation of Pumping Groundwater on Two-layer Soft Soil Structure with Porous Media

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Journal of Wuhan University of Technology(Materials Science) 2002年第2期17卷 66-69页

作者：管昌生 ZHOUJia-ze PENGShao-min JIANGCang-ru wuhanuniversityoftechnology WuhanInstituteofScienceandTechnology

Based on random theory, fluid dynamics , porous media and soil mechanics, the porosity and random characteristic of the two-layer soft soil in Wuhan region were studied in this paper. The random seepage coefficient on the two-layer soft soil was analyzed, and the seepage model and its random distribution Junction mere given. The groundwater flow differential equations related to the two layer soft soil structure were also established. The evaluation procedure of effect boundary on the pumping water in deep foundation pit was put forward. Moreover , with an engineering example, the probability distribution on random boundary prediction for pumping water of foundation pit was computed.

关键词： groundwater random simulation seepage parameter deep foundation pit

The Quantum Chemistry Calculation and Thermoelectricsof Bi-Sb-Te Series

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Journal of Wuhan University of Technology(Materials Science) 2002年第2期17卷 6-9页

作者：闵新民 HONGHan-lie ANJi-ming wuhanuniversityoftechnology

The density junction theory and discrete variation method ( DFT - DVM) was used to study correlation between composition, structure, chemical bond, and property of thermoelectrics of Bi-Sb-Te series. 8 models of Bi20-xSbxTe32(x = 0,2,6,8,12,14,18 and 20) were calculated. The results show that there is less difference in the ionic bonds between Te( I)-Bi(Sb) and Te(Ⅱ)-Bi(Sb) , but the covalent bond of Te(Ⅰ)-Bi( Sb ) is stronger than that of Te(Ⅱ)-Bi( Sb ) . The interaction between Te(Ⅰ) and Te(Ⅰ) in different layers is the weakest and the interaction should be Van Der Wools power. The charge of Sb is lower than that of Bi, and the ionic bond of Te-Sb is weaker than that of Te-Bi. The covalent bond of Te-Sb is also weaker than that of Te-Bi. Therefore, the thermoelectric property may be imfiroved by adjusting the electrical conductivity and thermal conductivity through changing the composition in the compounds of Bi-Sb-Te. The calculated results are consistent with the experiments.

关键词： bismuth telluride thermoelectric structure and property quantum chemistry calculation

Fatigue Defect of Layer Steel Fiber Reinforced Concrete

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Journal of Wuhan University of Technology(Materials Science) 2003年第1期18卷 65-68页

作者：陈应波 wuhanuniversityoftechnology

An experimental study is carried out on fatigue defect of layer steel fiber reinforced concrete (LSFRC). Based on experimental data,the various relation curves are given corresponding to different stress levels 0.9, 0.85, and 0.8. Furthermore, the fatigue defect degree is defined, and the strain cycle ratio equations and defect cycle ratio equations with the correlation coefficients very close to 1, are regressed in terms of the cubic polynomial,of which the fittings are *** addition,the results show that the fatigue defect of LSFRC presents three phase development regularity *** in comparison with the plain concrete,the third phase of the fatigue defect of LSFRC is longer, therefore the fatigue failure of LSFRC is more *** mechanism of the fatigue defect is discussed too.

关键词： LSFRC fatigue fatigue defect degree fatigue defect equation

Quantum Chemistry Calculation on Oxygen and Nitrogen Adsorption in Carbon Nanotude

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Journal of Wuhan University of Technology(Materials Science) 2003年第1期18卷 1-3页

作者：闵新民 wuhanuniversityoftechnology

Oxygen and nitrogen adsorption in single walled carbon nanotube (SWCNT) is studied by density function and discrete variational (DFT-DVM) *** models of O 2 and N 2 adsorption in the SWCNT are optimized based on the energy *** calculated results of density of state,populations and energy gaps of the molecular orbitals show that oxygen adsorption in SWCNT increases the carbon nanotube`s electrical conductivity more notably than nitrogen adsorption,which is consistent with the experiment.

关键词： single walled carbon nanotube quantum chemistry calculation adsorption electronic conductivity